at daggers drawn

at daggers drawn

in a state of bitter enmity

The image here is of the drawing of daggers as the final stage in a confrontation before actual fighting breaks out. Although recorded in 1668, the expression only became common from the early19th century onwards.

RELATED IDIOMS :

look daggers at

glare angrily or venomously at

The expression speak daggers is also found and is used by Shakespeare's Hamlet in the scene in which he reproaches his mother.